Pages

01 April 2018

Tetrahedral Geometry of Water Found to Account for its Remarkable Properties ~ John Russo, Kenji Akahane and Hajime Tanaka ~ 26 March 2018

The tetrahedron, octahedron and icosahedron ~ building blocks of the Universe, as proposed by Buckminster Fuller and currently a hot topic for aware scientists and researchers.

When I was in school, I remember a long discussion with classmates when we learnt about how ice would expand in volume, compared to its previous liquid state. This didn't make sense to me, and I refused to accept the standard explanation of "Unusual Properties of Water". Since then, I've always been fascinated with water and its mysterious characteristics ~ the real answers always lie outside of mainstream "science".

Water is the most common and yet least understood material on Earth. Despite its simplicity, water tends to form tetrahedral order locally bP directional hydrogen bonding. This structuring is known to be responsible for a vast array of unusual properties, e.g., the density maximum at 4 ◦C, which play a fundamental role in countless natural and technological processes, with the Earth’s climate being one of the most important examples. By systematically tuning the degree of tetrahedrality, we succeed in continuously interpolating between water-like behavior and simple liquid-like behavior. Our approach reveals what physical factors make water so anomalous and special even compared with other tetrahedral liquids. ---John Russo,Kenji Akahane, and Hajime Tanaka. Water-like anomalies as a function of tetrahedrality. PNAS, March 26, 2018.

The properties of water have fascinated scientists for centuries, yet its unique behavior remains a mystery.

Published this week in the journal Proceedings of the National Academy of Sciences, a collaboration between the Universities of Bristol and Tokyo has attempted a novel route to understand what makes a liquid behave like water.

When compared to an ordinary liquid, water displays a vast array of anomalies. Common examples include the fact that liquid water expands on cooling below 4 C, which is responsible for lakes freezing from the top rather than the bottom.

In addition, the fact that water becomes less viscous when compressed, or its unusually high surface tension, allows insects to walk on water's surface.

These and many other anomalies are of fundamental importance in countless natural and technological processes, such as the Earth's climate, and the possibility of life itself. From an anthropic viewpoint, it is like the water molecule was fine-tuned to have such unique properties.

Starting from the observation that the properties of water seem to appear fine-tuned, a collaboration between Dr John Russo from the University of Bristol's School of Mathematics and Professor Hajime Tanaka from the University of Tokyo, harnessed the power of powerful supercomputers, using computational models to slowly "untune" water's interactions.

This showed how the anomalous properties of water can be changed and eventually reduced to those of a simple liquid. For example, instead of floating on water, the density of ice can be changed continuously until it sinks, and the same can be done with all water anomalies.